1. The Axial Skeleton
Chapter 7

2. I. Skeletal Divisions (206 bones)
Axial Skeleton (80 bones)
Forms longitudinal axis of the body
Consists of:
Skull
Vertebral column
Ribs
Sternum

3. Appendicular Skeleton (126 bones)
Consists of
Pectoral girdle
Pelvic girdle
Bones of the limbs

4. II. The Skull (22 bones) Functions Protects
Guards entrances to digestive & respiratory systems

5. Cranium (braincase) (8 bones)

6. 1. Occipital Bone (1 bone)
Forms posterior & inferior surfaces

7. 2. Parietal Bones (2 bones)
Forms superior & lateral surfaces

8. 3. Frontal Bone (1 bone)
Forms anterior portion of skull & roof of orbits

9. 4. Temporal Bones (2 bones)
Surrounds & protects sense organs of inner ear

10. 5. Sphenoid Bone (1 bone)
Cross-brace that strengthens sides of skull (looks like a bat)

11. 6. Ethmoid Bone (1 bone)
Forms roof of nasal cavity, part of nasal septum

12. Facial Bones ( 14 bones)

13. 1. Maxillary Bones (2 bones)
Supports the teeth

14. 2. Palatine Bones (2 bones)
Forms portion of hard palate

15. 3. Lacrimal Bones (2 bones)
Forms medial wall of orbits

16. 4. Nasal Bones (2 bones)
Supports superior portion of bridge of nose

17. 5. Zygomatic Bones (2 bones)
Forms rim & lateral wall of orbits

18. 6. Vomer Bone (1 bone)
Forms interior portion of bony nasal septum

19. 7. Inferior Nasal Conchae (2 bones)
Creates turbulence in air passing through nasal cavity
WHY???

20. 8. Mandible Bone (1 bone)
Lower jaw

21. Sinuses Makes bones lighter
Produces mucus to moisten & clean air in and near the sinuses

22. E. Sutures- Immovable joints connected with dense fibrous connective tissue
Lambdoidal Suture- between occipital & parietal bones
Coronal Suture- between frontal and parietal bones
Sagittal Suture- between parietal bones

23. 4. Squamosal Sutures- between temporal & parietal bones
5. Fontanels- fibrous area between cranial bones in infants
a. allow skull to be distorted/squished to ease delivery
b. the frontal fontanel persists until a child is nearly 2 yrs. old

24. Sutures of the Skull

25. F. Associated Bones of the Skull (7)
Auditory Ossicles (6 bones)
3 bones per ear
malleus, incus & staples

26. Hyoid Bone (1 bone) Supports larynx
Only free standing bone not connected to another bone

27. III. The Vertebral Column
- 33 total bones

28. A. Functions of the V.C. Provide a column of support
Bear the weight of the head, neck & trunk
Protect the spinal cord
Helps maintain an upright body position
(Sitting/Standing)

29. B. Divisions of the V.C. Cervical Region a) Made of 7 vertebrae
b) Constitutes the neck region
c) Labeled C1-C7 (Superior to Inferior)
i. C1 is called the Atlas
-holds up the head
- Articulates w/ occipital condyles
- Allows “yes” movement
ii. C2 is called the Axis
- Pivots around the Atlas
- Allows “no” movement

30. Thoracic Region
a) Made of 12 vertebrae
b) Constitutes the chest/upper back region
c) Labeled T1-T12 (Superior to Inferior)
d) Articulate with the ribs

31. Lumbar Region
a) Made of 5 vertebrae
b) Constitutes the lower back region
c) Labeled L1-L5 (Superior to Inferior)
d) Large, weight-bearing bones
e) Provides site for muscle attachment

32. 4. Sacrum
a) Made of 5 fused vertebrae
b) Constitutes the posterior portion of the pelvis
c) Provides protection for reproductive, digestive, & urinary organs

33. 5. Coccyx
a) Made of 3-5 fused vertebrae
b) Also known as the tailbone

34. 5 Divisions of the V.C.
Cervical
Thoracic
Lumbar
Sacrum
Coccyx

35. C. Spinal Curvatures 1) Thoracic Curvature 2) Sacral Curvature
- 1) & 2) are known as Primary or Accommodation curves b/c they appear in fetal development

36. 3) Cervical Curvature
4) Lumbar Curvature
- 3) & 4) are known as Compensation curves b/c they develop as we learn to walk (help shift weight over legs)

37. 4 Spinal Curvatures

38. A. Consists of the thoracic vertebrae, ribs, & sternum
IV. The Thoracic Cage
A. Consists of the thoracic vertebrae, ribs, & sternum

39. B. Functions Protects the heart, lungs, thymus & other structures
Serves as an attachment point for muscles

40. C. The Ribs 12 pair of curved, flat bones
Originate on or between thoracic vertebrae
End in the wall of the thoracic cavity

41. D. Kinds of Ribs True/Vertebrosternal Ribs
a) First 7 pairs, most superior
b) Connected to sternum by cartilaginous extensions

42. False/Vertebrochondral Ribs
a) Ribs 8-12
b) The cartilage on the ends of these ribs fuse together with rib 7

43. 3) Floating Ribs
a) Last 2 pairs (11th & 12th)
b) Not connected to sternum at all

44. E. The Sternum (breastbone)
Flat bone
Forms the anterior midline of the thoracic wall

45. F. Divisions of the Sternum
Manubrium
a) Most superior part of the sternum
b) Triangular shaped
c) Articulates w/ the clavicles & the cartilage of the 1st pairs of ribs

46. Body
a) Tongue shaped
b) Costal Cartilage from pairs 2-7 attach here

47. Xiphoid Process
a) Most inferior part of sternum
b) Smallest part of sternum
c) The diaphragm & some abdominal muscles attach here

48. The Thoracic Cage